Heat shield panel retainer

ABSTRACT

A retainer for connecting two panels of a heat shield assembly, the retainer comprising: a central elongate panel having a length 1 and a width w, a top end, a bottom end and first and second long sides extending from the top end to the bottom end; a first side panel extending along the first long side of the central elongate panel and a second side panel extending along the second long side of the central elongate panel; and wherein the central elongate panel is corrugated, with corrugations running along the length of the central elongate panel from the top end to the bottom end.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, EP PatentApplication No. 22461569.0, filed Jun. 9, 2022 and titled “HEAT SHIELDPANEL RETAINER,” which is incorporated by reference herein in itsentirety for all purposes.

FIELD

The present disclosure relates to a retainer for connecting panels orsegments of a heat shield assembly for a wheel for a vehicle especially,but not exclusively, for an aircraft wheel.

BACKGROUND

Wheels on aircraft and other vehicles are often provided with a brakeassembly comprising a stack of brake discs mounted inside the wheel,within the tube well of the wheel. The brake operates by compressing thebrake discs together to slow and stop rotation of the wheel. Thefriction between the pressed brake discs generates a large amount ofheat which can cause damage to the wheel and/or tires. It isconventional to provide a heat shield between the brake assembly and thewheel rim or tube well to reduce the effects of the heat generated bybraking on the wheel parts. The heat shield can also catch hot brakematerial that is ejected from the brake discs during braking, before itstrikes the wheel.

Various types of heat shield are known but, typically, heat shields arein the form of metal sheets or panels provided concentric with the wheeltube well and spaced a small distance from the tube well. The heatshield can be provided as a single cylindrical piece but more typicallyis formed as a number of arcuate panels or segments that are attachedtogether to form a complete cylindrical heat shield.

Particularly with the increased use of carbon disc brakes, which havegreater energy absorption capability than steel brakes and aresignificantly lighter, but which are larger than steel brake discs, itis important for the heat shields to be robust. There is, however, alsoa need for them to be as simple and lightweight as possible. In aircraftin particular, but also in other vehicles with braked wheels, there is aneed to minimize the weight and size of the wheel assembly. Heat shieldsare therefore, often made of thin metal panels but may be arranged astwo or more layers of panels with an insulation gap therebetween.

Because of the high temperature and high stress/vibrational environmentsthat braked wheels operate in and high centrifugal forces acting on theheat shields, as well as changes in tire pressure, the heat shield canbe caused to deform and/or deflect. This can cause high stresses on theheat shield and can cause the heat shield to come into contact with thewheel tube well which can, in turn, result in wheel abrasion. Theconnectors used to join adjacent panels comprise two engaging orinterleaving hook parts resulting in a seam that is thicker than theindividual panels themselves and the seams provide points around theheat shield that are even more likely to contact the wheel tube wellduring movement and/or if the heat shield panels are deflected ordeformed. This is even more of an issue for carbon brakes because theyare larger and so there is less space between the discs and the wheel.Flatter retainers have also been designed, that take the form of acentral panel and side wings or panels. The central panel is providedwith a hole at the top end through which a bolt can pass, and a foot atthe bottom to be supported by a torque bar. The side panels extendpartly across respective adjacent heat shield panels. The retainer andtorque bar combine to connect/retain the heat shield panels. Suchretainers are made of relatively thin sheets of metal to maintain a lowprofile. The retainer being thin, provides an area of weakness in theheat shield assembly, and is the area where the greatest deflection andplasticity appears. The retainer may not be strong enough to preventdeflection of the wings and the heat shield panels they support, incertain conditions. This can therefore lead to the heat shield panelsmaking contact with the tube well, thus resulting in abrasion.

There is a need for a heat shield assembly which is less prone todeflection and deforming and also an improved retainer, so as to avoidor reduce damage to the heat shield and to avoid or reduce wheelabrasion.

SUMMARY

According to the present disclosure, there is provided a retainer forconnecting two panels of a heat shield assembly, the retainercomprising: a central elongate panel having a length 1 and a width w, atop end, a bottom end and first and second long sides extending from thetop end to the bottom end; a first side panel extending along the firstlong side of the central elongate panel and a second side panelextending along the second long side of the central elongate panel; andwherein the central elongate panel is corrugated, with corrugationsrunning along the length of the central elongate panel from the top endto the bottom end.

BRIEF DESCRIPTION OF THE DRAWINGS

The assembly according to the disclosure will be described, by way ofexample only, with reference to the drawings. Variations andmodifications are possible within the scope of the claims.

FIG. 1 shows an example of a heat shield in a wheel;

FIG. 2 shows a conventional retainer forming the connection between heatshield panels as in FIG. 1 ;

FIG. 3 shows a profile view of a retainer as shown in FIG. 2 ;

FIG. 4 is a view of a retainer according to the disclosure;

FIG. 5A is a detail of the top end of a retainer as shown in FIG. 4 ;

FIG. 5B is a detail of the bottom end of the retainer of FIG. 4 ;

DETAILED DESCRIPTION

FIG. 1 shows a section of a typical wheel assembly comprising a wheelrim or tube well 1 having an outer diameter surface 10, on which a tire(not shown) will usually be mounted, and an inner diameter surface 20defining an interior cavity in which a brake assembly (not shown) willtypically be arranged around a wheel hub 30. The hub 30 would beattached by bearing to an axle (not shown). The hub 30 is connected tothe wheel rim 1 via a web 40. Rotor disc drive lugs (or torque bars) 50extend axially across the tube well 1 for engagement with the brakediscs.

To protect the wheel rim 1 from the heat generated during hard brakingor from brake disc material ejected during braking, a heat shield ismounted to the inner diameter surface 20 of the wheel. The heat shieldmay be a single tubular shield or, as shown in this example, may beformed of several heat shield panels 60 provided between the rotor drivelugs 50. The heat shield/panels 60 is in the form of an arcuate thinmetal sheet or several thin metal sheets and is attached to the wheel soas to be spaced apart from the wheel inner diameter surface by a smallinsulation gap (not shown). Where the heat shield is made of a number ofpanels or segments attached together, the adjoining edges 60 a, 60 b ofthe panels are connected and retained by means of retainers 70. Theretainers 70 each define a seam between adjacent panels.

A typical retainer 70 is shown in FIGS. 2 and 3 . Such a retainer 70 isformed of a shaped metal sheet having a main panel 70 a that, in use,will define the seam between two adjacent heat shield panels whenpositioned between their adjacent edges 60 a, 60 b. The main panel 70 ahas a length 1 and a width w essentially corresponding to the dimensionsof a drive lug 50. The top of the main panel is provided with a tab 61within which is formed a hole 62 to receive a bolt or fastener (notshown). The other end of the main panel is provided with a foot 63 tosupport the retainer in place against the lug 50. The foot 63 may alsohave a hole therethrough, in which an end pin of the lug can be located.Typically, cut-outs 66 are formed between the main panel and the foot.Extending along each of the long sides of the main panel is a side panelor wing 70 b, 70 b′. A bend 71 provides the transition from the mainpanel 70 a to the wing 70 b, 70 b′.

In use, the retainer is located between adjacent edges of adjacent heatshield segments such that the wings extend over part of the respectivesegment to retain the segments to form the circular heat shield at theappropriate distance from the tube well.

As mentioned above, in the harsh braking conditions experienced by e.g.wheels on an aircraft landing gear, high temperatures are reached andpieces of hot material can break off from the rotor discs. All of thiscan cause the heat shield panels to deform or deflect and be damagedand/or to contact the wall by being deflected into the insulation gapbetween the heat shield and the tube well interior surface. Because theretainer is made of relatively thin, light material, deformation of thepanels can cause the retainer to deflect outwards and contact the wheelrim and this can result in damage and wheel abrasion. Also, if theretainers are not sufficiently strong to retain the heat shield panelsin such conditions, the heat shield panels themselves can also contactthe wheel. This can cause wheel abrasion and/or heat shielddamage/abrasion and require the entire wheel assembly to be replaced.

FIG. 4 shows a retainer 100 modified according to the disclosure to addstiffness and strength to the heat shield whilst minimizing thethickness of the retainer in the space between the heat shield and thewheel, so reducing the effects of deformation or deflection of thepanel, to avoid or mitigate the problems mentioned above.

As shown in FIG. 4 , the shape of the retainer is similar to that shownin FIGS. 2 and 3 in that the retainer 100 is formed of a sheet of metalshaped to define an elongate central panel 101 flanked by two sidepanels or wings 102, 102′. Similarly to the known design, one end of thecentral panel is provided with a tab 103 through which a fastener hole104 may be formed and the other end of the central panel is formed as afoot 105 which may have a hole 106 therethrough to retain a torque bar(not shown). Rather than the central panel being formed merely by a flatmetal sheet as in the known design, however, in the modified design ofthis disclosure, the central panel is corrugated as best seen in FIGS.5A and 5B. The corrugations 200 run along the full length of theretainer, from the top end to the bottom end, which significantly addsto the strength and stiffness of the retainer.

Whilst the retainer can be formed as a single piece, it is possible toform the retainer as three separate parts, as can be seen in FIGS. 5Aand 5B, whereby a top end portion 101 a of the corrugated centralelongate panel is formed as one part with the tab 103, and a bottom endpart 101 b of the central elongate panel is formed in a part with thefoot 106, and these parts are then attached e.g. by welding, to themiddle part 101 c of the central elongate panel.

In addition to adding strength to the retainer, the corrugated formincreases the surface area of the retainer and so improves its thermalproperties.

Depending on application and design requirements, the number ofcorrugations can be increased or decreased.

In use, the central panel 101 is located at the seam between adjoiningedges of adjacent panels and the side panels 102, 102; extend partiallyacross the respective heat shield panel to retain the heat shield panelsin the heat shield configuration and spaced from the tube well by theinsulation gap. With the added stiffness and strength provided by thecorrugations, if the heat shield panels deflect, the retainer will bestrong and stiff enough to retain the heat shield panels away from theinner diameter of the tube well without the retainer or the heat shieldpanels contacting the wheel and causing abrasion.

In addition, in the example shown, in forming the corrugations, there isno need for any cut-outs which further adds to the strength of theretainer. Because of the added strength, the retainer is less a regionof weakness than in the known designs.

The corrugations combine to increase the stiffness of the retainer, andso the depth of each individual corrugation can still be relativelysmall. The retainers in the space between the heat shield and the wheelrim, therefore, have a relatively small profile and are thus less likelyto contact the wheel rim if the panel is deformed or deflected than inconventional assemblies.

In the example shown, the depth d of the corrugations 200 isapproximately the same as the distance by which the foot 106 extendsradially inwards. The modified retainer does not, therefore, take up anyadditional space compared to the known design.

In an example, each pair of adjacent heat shield panels is provided witha retainer between their adjoining edges. In other examples, two or moreretainers may be positioned between each pair of heat shield panels.

To assemble the heat shield, two adjacent panels are connected by meansof the retainer.

The retainer of this disclosure provides additional strength to the heatshield and a secure connection between heat shield panels, whilstminimizing the risk of wheel abrasion due to deformation or deflectionof the panels.

1. A retainer for connecting two panels of a heat shield assembly, theretainer comprising: a central elongate panel having a length 1 and awidth w, a top end, a bottom end and first and second long sidesextending from the top end to the bottom end; a first side panelextending along the first long side of the central elongate panel and asecond side panel extending along the second long side of the centralelongate panel; and wherein the central elongate panel is corrugated,with corrugations running along the length of the central elongate panelfrom the top end to the bottom end.
 2. The retainer of claim 1, furthercomprising a tab extending from the top end.
 3. The retainer of claim 2,further comprising a fastening hole formed in the tab.
 4. The retainerof claim 1, further comprising a foot at the bottom end.
 5. The retainerof claim 4, further comprising a locating hole in the foot.
 6. Theretainer of claim 1, the central panel and the first and second sidepanels being formed from a single piece of sheet metal.
 7. The retainerof claim 1, wherein the retainer is formed of a top section, a middlesection and a bottom section, the top section welded to one end of themiddle section and the bottom section welded to the other end of themiddle section.
 8. A heat shield assembly for a wheel assembly,comprising a plurality of arcuate heat shield panels arranged to beconnected together to form a heat shield to be attached to the interiorof a wheel, and the retainer as claimed in claim 1, for attachingadjacent panels.
 9. The heat shield assembly as claimed in claim 8,wherein one or more retainers is provided between each pair of adjacentpanels.
 10. The heat shield assembly of claim 8, wherein each panelcomprises two heat shield panel layers arranged radially adjacent eachother and wherein the retainer prevents relative movement of the layers.11. A wheel assembly comprising a wheel rim having a radially innersurface and a radially outer surface, and the heat shield assembly asclaimed in claim 8, attached to and having the radially outer surfaceradially spaced from the radially inner surface of the wheel rim. 12.The wheel assembly of claim 11, further comprising a plurality of torquebars arranged around the radially inner surface of the heat shield, atorque bar positioned along the central elongate panel of each retainer.13. The wheel assembly of claim 11 being the wheel assembly for thelanding gear of an aircraft.